1. Field of Invention
This invention relates to a sensor circuit on a ceramic substrate providing reliable continuous monitoring of fluid pressure in a closed chamber. The circuit is used in combination with a wiper arm having two or more contacting points that passes over conductor contact pads of the circuit and converts the position of the contacting points of the wiper arm to predetermined resistance values which are converted into fluid pressures in a closed chamber, for example, to record the oil pressure in an automobile crankcase. The circuit contains means to maintain continuous electrical contact between at least one of the contacting points of the wiper arm and at least one conductor contact pad.
2. Prior Art
Existing circuit sensors, for example, that disclosed in United States Patent 4,667,518 use wiper arm means to convert a predetermined resistance value into a pressure value in an automobile crankcase. However vibration produced, for example, by the automobile engine can cause the wiper arm to jump off the the face of the sensor circuit, breaking the electrical contact and measurement of pressure. Overheating of sensor circuits has resulted in distortion or even interruption of electrical output.
It is an object of this invention to provide a thick film sensor circuit capable of continuous electrical contact between the wiper arm and contact pad conductors.
It is another object of this invention to provide a thick film sensor circuit design to dissipate the heat generated on the circuit safely over the maximum substrate surface area.